首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4521篇
  免费   471篇
  国内免费   29篇
耳鼻咽喉   34篇
儿科学   115篇
妇产科学   41篇
基础医学   484篇
口腔科学   196篇
临床医学   565篇
内科学   995篇
皮肤病学   98篇
神经病学   361篇
特种医学   476篇
外科学   880篇
综合类   29篇
预防医学   358篇
眼科学   40篇
药学   136篇
中国医学   4篇
肿瘤学   209篇
  2023年   87篇
  2022年   62篇
  2021年   135篇
  2020年   105篇
  2019年   131篇
  2018年   174篇
  2017年   123篇
  2016年   156篇
  2015年   179篇
  2014年   224篇
  2013年   243篇
  2012年   255篇
  2011年   266篇
  2010年   153篇
  2009年   198篇
  2008年   173篇
  2007年   208篇
  2006年   193篇
  2005年   165篇
  2004年   107篇
  2003年   109篇
  2002年   95篇
  2001年   76篇
  2000年   66篇
  1999年   77篇
  1998年   82篇
  1997年   105篇
  1996年   93篇
  1995年   74篇
  1994年   72篇
  1993年   70篇
  1992年   49篇
  1991年   47篇
  1990年   60篇
  1989年   69篇
  1988年   45篇
  1987年   45篇
  1986年   45篇
  1985年   45篇
  1984年   19篇
  1983年   26篇
  1982年   31篇
  1981年   34篇
  1980年   21篇
  1979年   23篇
  1978年   15篇
  1977年   17篇
  1976年   19篇
  1975年   13篇
  1971年   9篇
排序方式: 共有5021条查询结果,搜索用时 663 毫秒
61.
CONTEXT: Advance directives promote patient autonomy and encourage greater awareness of final care options while reducing physician and family uncertainty regarding patient preferences. PURPOSE: To investigate differences in decision making authority and the use of advance directives among nursing home residents admitted from urban and rural areas. METHODS: A total of 551,208 admission assessments in the Minimum Data Set were analyzed for all residents admitted to a nursing facility in 2001. Using the Rural Urban Commuting Areas (RUCA) methodology and ZIP code of primary residence before admission, these residents were classified into 4 urban/rural areas. FINDINGS: Residents from rural areas were significantly more likely to have executed a durable power of attorney for health care or for financial decisions than residents admitted from the other areas, with the largest differences observed between residents admitted from urban and rural areas. Almost 6 residents in 10 from urban areas had no advance directives in place at admission compared with only 4 residents in 10 admitted from rural areas. CONCLUSIONS: Health providers and social workers in both rural and urban areas should advise patients about the value of advance directives.  相似文献   
62.
Antifungal activity of natural products is being studied widely. Saponins are known to be antifungal and antibacterial. We have isolated eight steroid saponins from Tribulus terrestris L. , namely TTS-8, TTS-9, TTS-10, TTS-11, TTS-12, TTS-13, TTS-14 and TTS-15. TTS-12 and TTS-15 were identified as tigogenin-3-O-β-D-xylopyranosyl(1→ 2)-[-β-D-xylopyranosyl( 1 → 3 ) 3-β- D-glucopyranosyl ( 1 → 4 )- 1- α-L-rhamnopyranosyl ( 1 → 2 ) 3-β-D-galactopyranoside and tigogenin-3-O-β-D-glucopyranpyranosyl(1→2)-[-β-D-xylopyranosyl(1→ 3)3-β-D-glucopyranosyl(1→4)-β-D-galactopyranoside, respectively. The in vitro antifungal activities of the eight saponins against six fluconazole-resistant yeasts, Candida albicans, Candida glabrata, Candida para psilosis , Candida tropicalis , Candida krusei , and Cryptococcus neo f ormans were studied using microbroth dilution assay. The results showed that TTS-12 and TTS-15 were very effective against several pathogenic candidal species and C. neoformans in vitro. It is noteworthy that TTS-12 and TTS-15 were very active against fluconazole-resistant C. albicans (MIC80 = 4.4, 9.4 mg/ml), C. neoformans (MIC80 =10.7, 18.7 mg/ml) and inherently resistant C. krusei (MIC80 =8.8, 18.4 mg/ml). So in vivo activity of TTS-12 in a vaginal infection model with fluconazole-resistant C. albicans was studied in particular. Our studies revealed TTS-12 also showed in vivo activities against fluconazole-resistant yeasts. In conclusion, steroid saponins TTS-12 and TTS-15 from Tribulus terrestris L. have significant in vitro antifungal activity against fluconazole-resistant fungi, especially TTS-12 also showed in vivo activity against fluconazole-resistant C. albicans.  相似文献   
63.
OBJECTIVE: We determined whether contrast-enhanced color Doppler sonography can differentiate benign from malignant enlarged cervical lymph nodes in head and neck tumors. SUBJECTS AND METHODS: Ninety-four enlarged lymph nodes in 39 adult patients (32 men and seven women; age range, 30-81 years) were examined with B-mode sonography and with unenhanced and contrast-enhanced color Doppler sonography. All patients had carcinoma of the oral cavity. Histologically, lymphadenitis was found in 57 nodes and metastases in 37 nodes. Geometric dimension, texture, and margin of the node and detection and location of vessels were noted. Histology and imaging findings were correlated. RESULTS: The transverse-to-longitudinal diameter ratio in combination with texture and margin analysis resulted in a correct diagnosis in only approximately 79% of the nodes. With contrast-enhanced color Doppler sonography, 86% of nodes showed vessels, and 28% of nodes showed vessels with this technique exclusively. Characteristic configurations were identified: hilar vessels with branching indicated lymphadenitis (sensitivity, 98%; specificity, 100%), and predominantly peripheral vessels indicated metastases (100%, 98%). These findings changed the diagnosis in 13 nodes, changed the therapy in four patients, and led to an incorrect diagnosis in one patient. CONCLUSION: Enlarged lymph nodes can be characterized as metastatic or inflammatory with high diagnostic accuracy on the basis of their vascular architecture as seen on contrast-enhanced color Doppler sonography.  相似文献   
64.
Skleromyxödem     
Scleromyxedema is a rare disorder that frequently affects multiple extracutaneous organ systems and is usually associated with monoclonal gammopathy. The pathogenesis of scleromyxedema is unknown. The clinical course is chronic and progressive and can lead to marked morbidity or death. The skin findings consist of multiple waxy papules and indurated plaques. Progressive skin involvement can lead to decreased mobility of the mouth and joints. Extracutaneous manifestations occur in the musculoskeletal or cardiovascular system, in the gastrointestinal or respiratory tract, or in the kidneys. There are no approved or evidence-based treatment options available for scleromyxedema. High-dose immunoglobulins are considered the treatment of choice, followed by lenalidomide (or thalidomide) and systemic glucocorticosteroids, or in severe cases even autologous hematopoetic stem cell transplantation. Long-term maintenance treatment is usually required and close clinical follow-up is necessary as recurrence of scleromyxedema is common after withdrawal of an effective therapy.  相似文献   
65.
66.
67.
68.
Buprenorphine is considered one of the most effective treatments for opioid use disorder and significantly reduces risk of overdose death. However, concerns about its diversion and misuse have often taken center stage in public discourse and in the design of practices and policies regarding its use. This has been to the detriment of many vulnerable patient populations, especially those involved in the criminal justice system. Policies that restrict access to buprenorphine in criminal justice and other settings due to concerns of diversion do not accurately reflect the relative risks and safety profile associated with it, creating unnecessary barriers that drive an illicit market of this much-needed medication. Although proper regulation of all controlled medications should be a priority, in most instances the benefits of buprenorphine highly outweigh its risks. In the midst of a national crisis, efforts should be focused on expanding, and not restricting, access to this lifesaving treatment.  相似文献   
69.
70.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号